May 31 is going to be interesting day, as it brings the launch of dual core processors on the desktop. Of course the hyper-threaded Pentium Extreme Edition 840 is sparsely available today - for example, it can be found at Dell - while the volume model Pentium D won't be around before June. Meanwhile, AMD managed to beat Intel in the profitable workstation/server space by shipping the dual core Opteron models x65/x70/x75. The second step of AMD's 2005 strategy is a desktop dual core product, freely adapted from what Intel arranged a month ago. That's what this preview is about.

The first surprise here is that unlike Intel, thermal issues did not force AMD to reduce average clock speeds to operate two processor cores on one physical chip. This means that AMD dual core processors should run exactly as fast as their single core versions running at the same clock speed. In contrast, the fastest Intel dual core will remain at 3.2 GHz, while the fastest single core clocks in at 3.8 GHz.

Switching from a 130 nm process to a 90 nm process using silicon on insulator (SOI) technology decreased AMD's mainstream thermal design power from a maximum of 89 Watts to 67 Watts, at up to 2.2 GHz (the Winchester 3500+). At the same time, the Athlon 64 FX 55 at 2.6 GHz keeps the thermal envelope wide enough (104 Watts TDP) to support the dual core chips on a large percentage of socket 939 systems already deployed to the market. In contrast, if you want to give the Pentium D a try, it will require a new motherboard, even though the physical socket was not changed.

A total of four dual core desktop processors, collectively named the Athlon 64 X2, will be officially released at May 31 (Intel has three Pentium D models, plus the Extreme Edition). Two X2 models will be based on the Manchester dual core with 512 kB L2 cache per core; two additional versions will make use of the Toledo design with 1 MB L2 cache per logical unit.

While the mainstream Manchester models will fit within a thermal envelope of 95 Watts, the higher performing versions will require a maximum of 110 Watts, which should be easily provided by any motherboard capable of handling an Athlon 64 FX 55. While these numbers represent a bold requirement, we should not forget that Intel's top model reaches a whopping 130 Watts at 3.2 GHz, and its average power consumption is somewhat higher, too. Interesting is the "tie" with respect to the power consumed at the mainstream level, as both competitors are head to head at 95 Watts.